Ecosystem services (ES) are the humans benefits derived from ecosystems. Since the Millennium Ecosystem Assessment (2005), many initiatives were taken to further develop this concept theoretically and to make it operational in daily policy. In Belgium, there is an urgent need to gain more insight into local ES. A crucial step is to bring together existing knowledge and expertise to inventory knowledge on the many important ES they deliver (provisioning services, such as fish, shellfish, reed,...; regulating services, such as water regulation and water purification,..; supporting services, such as primary production, nutrient cycling,. .; and cultural services, such as recreation).
The ecosystem services concept has an enormous potential to reach a sustainable management of ours open space and nature landscapes. Finding a balance between eco- and anthropo-centric values has been always a difficult exercise. The ecosystem services concept shows that this contrast is only an appearance. Considering nature and landscapes as producers of ecosystem services is a promising concept which helps to valuate more the nature and the landscapes. The continued degradation of ecosystems may have important economic and social impacts. The systematic replacement of “free” ecosystem services by expensive technical solutions leads to a larger organisational and financial cost for the society. The ecosystem services concept offers a unique framework where social, economic and environmental aspects can be integrated. Moreover the economic valuation of ecosystem services offers clearly possibilities to evaluate the social and economic values of ecosystems and in this this way to play a role in policy making. Building such process of valuation of ecosystem services is only possible by using the present basic knowledge. Both the social demand for ecosystem services as the ecological mechanisms which provide those services, are subject to a large variability and heterogeneity.